Procedure: In a non-stick pan, combine the water and sugar and heat the mixture until it comes to a boil. To this liquid, add the walnut and cocoa powders, cook until the mixture starts leaving the sides of the pan. Transfer onto a greased plate, and knead the mixture. Let it set for a minute and cut into squares. You can get creative and use cookie cutters. I dusted the squares with powdered sugar. A completely optional thing to do.